hey everyone I have a 1998 ford explorer xlt and when im driving(shifting gears)or speed up I hear a extremely loud ratting noise coming from underneath the vehicle.It seems to be coming from where the catalytic converter is but no one seems to be sure.As for an example of the sound would be a rock loose in a can when shaken up.Any advice or suggestions of where to start or look for the problem would be found would be greatly appreciated.

 

Have you checked the heat shroud on the catalytic converter? the pins holding them tend to rot and the shield will rattle. Ive fixed my gals car by putting in bolts with lock nuts in place of the pins and the rattle went away.

 

You can also buy large hose clamps to fasten around the whole convertor which sadwiches the upper and lower shields to the convertor. Plus installation is rather quick.